Systems and methods for reducing a radial distance of a collimator assembly occupying

ABSTRACT

A device may include a collimator positioned between a radiation source of a scanner and a bore of the scanner. The bore may include a detecting region configured to accommodate a subject. The collimator may be configured to prevent at least one portion of radiation rays emitted from the radiation source from being incident on the subject. The device may further include a first filter and a second filter. The first filter may be positioned between the radiation source and the collimator. The second filter may be positioned between the collimator and the bore. The first filter and the second filter may be configured to adjust a distribution of radiation impinging upon the subject.

TECHNICAL FIELD

The present disclosure generally relates to medical imaging systems, andin particular, the medical imaging systems having a collimator assemblywith a short occupied radial distance.

BACKGROUND

High energy beams such as x-rays are widely used for medical diagnosisor radiation therapy in, for example, computed tomography (CT) systems,positron emission tomography (PET) systems, single photon emissioncomputed tomography (SPECT) systems. In many of these applications, acollimator is often utilized to limit or collimate high energy beams(e.g., X-rays) emitted from a radiation source. For example, in a CTsystem, a collimator assembly may be used to collimate X-ray beamsemitted from an X-ray source, and the collimated X-ray beams may impingeupon a subject to be scanned (e.g., a patient). The collimator assemblymay reside between the X-ray source and the bore accommodating thesubject. The X-ray efficiency in such configuration may be inverselyproportional to the squared distance between the subject and X-raysource. Additionally, a larger bore, which accommodates the subject, ismore desirable because it may be easier for a patient to get into thebore. The smaller a radial distance of a collimator assembly occupying,the smaller the distance between the subject and X-ray source may be,and the larger the bore may be designed to be. Therefore, it isdesirable to provide systems for reducing the occupied radial distanceof the collimator assembly as small as possible, that can make systempurchase, operation, and maintenance costs lower.

SUMMARY

In one aspect of the present disclosure, a device is provided. Thedevice may include a collimator positioned between a radiation source ofa scanner and a bore of the scanner. The bore may include a detectingregion configured to accommodate a subject. The collimator may beconfigured to prevent at least one portion of radiation rays emittedfrom the radiation source from being incident on the subject. The devicemay further include a first filter and a second filter. The first filtermay be positioned between the radiation source and the collimator. Thesecond filter may be positioned between the collimator and the bore. Thefirst filter and the second filter may be configured to adjust adistribution of radiation impinging upon the subject.

In some embodiments, the second filter may include a first surfacefacing the collimator. The shape of the first surface may conform to ashape of the collimator.

In some embodiments, the second filter may include a second surfacefacing the bore. The shape of the second surface may conform to a shapeof the bore.

In some embodiments, the second filter may be integrated into a coverfor encompassing the bore.

In some embodiments, the first filter may include a surface facing thecollimator. The shape of the surface facing the collimator may conformto a shape of the collimator.

In some embodiments, the first filter may include at least one of abowtie filter or a wedge filter.

In some embodiments, the second filter may include at least one of abowtie filter or a wedge filter.

In some embodiments, the first filter may include a first material, andthe second filter may include a second material. The first material orthe second material may include at least one of plastic, graphite, oraluminum.

In some embodiments, the first material may be different from the secondmaterial.

In some embodiments, the first material may be same as the secondmaterial.

In some embodiments, the device may further include a measurementcomponent configured to determine at least one of an intensity ofradiation beams that reaches the first filter or a location of theradiation source.

In some embodiments, the first filter may have a surface facing theradiation source. The surface may form a concave. The measurementcomponent may be located in the concave.

In some embodiments, the device may further include a motion componentconfigured to move at least one of the collimator, the first filter, orthe second filter.

In some embodiments, the device may further include a third filter. Thethird filter may be a flat filter.

In another aspect of the present disclosure, a system for reducing aradial distance of a collimator assembly occupying is provided. Thesystem may include a scanner including a radiation source and a bore.The system may also include a collimator assembly positioned between theradiation source and the bore of the scanner. The bore may include adetecting region configured to accommodate a subject. The collimatorassembly may include a collimator positioned between the radiationsource and the bore. The collimator may be configured to prevent atleast one portion of radiation rays emitted from the radiation sourcefrom being incident on the subject. The collimator assembly may furtherinclude a first filter and a second filter. The first filter may bepositioned between the radiation source and the collimator. The secondfilter may be positioned between the collimator and the bore. The firstfilter and the second filter may be configured to adjust a distributionof radiation impinging upon the subject.

In some embodiments, the second filter may include a first surfacefacing the collimator. The shape of the first surface may conform to ashape of the collimator.

In some embodiments, the second filter may further include a secondsurface facing the bore. The shape of the second surface may conform toa shape of the bore.

In some embodiments, the first filter may include a surface facing thecollimator. The shape of the surface facing to the collimator mayconform to a shape of the collimator.

In some embodiments, the first filter may include at least one of abowtie filter or a wedge filter.

In some embodiments, the second filter may include at least one of abowtie filter or a wedge filter.

Additional features will be set forth in part in the description whichfollows, and in part will become apparent to those skilled in the artupon examination of the following and the accompanying drawings or maybe learned by production or operation of the examples. The features ofthe present disclosure may be realized and attained by practice or useof various aspects of the methodologies, instrumentalities, andcombinations set forth in the detailed examples discussed below.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is further described in terms of exemplaryembodiments. These exemplary embodiments are described in detail withreference to the drawings. These embodiments are non-limiting exemplaryembodiments, in which like reference numerals represent similarstructures throughout the several views of the drawings, and wherein:

FIG. 1 is a schematic diagram illustrating an exemplary imaging systemaccording to some embodiments of the present disclosure;

FIG. 2 is a schematic diagram illustrating an exemplary scanneraccording to some embodiments of the present disclosure;

FIG. 3 is a schematic diagram illustrating an exemplary collimatorassembly according to some embodiments of the present disclosure;

FIG. 4 is a schematic diagram illustrating an exemplary collimatorassembly according to some embodiments of the present disclosure;

FIG. 5 is a schematic diagram illustrating an exemplary collimatorassembly according to some embodiments of the present disclosure; and

FIG. 6 is a schematic diagram illustrating an exemplary collimatorassembly according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth by way of examples in order to provide a thorough understanding ofthe relevant disclosure. However, it should be apparent to those skilledin the art that the present disclosure may be practiced without suchdetails. In other instances, well-known methods, procedures, systems,components, and/or circuitry have been described at a relativelyhigh-level, without detail, in order to avoid unnecessarily obscuringaspects of the present disclosure. Various modifications to thedisclosed embodiments will be readily apparent to those skilled in theart, and the general principles defined herein may be applied to otherembodiments and applications without departing from the spirit and scopeof the present disclosure. Thus, the present disclosure is not limitedto the embodiments shown, but to be accorded the widest scope consistentwith the claims.

The terminology used herein is to describe particular exampleembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” may be intended to include theplural forms as well, unless the context clearly indicates otherwise. Itwill be further understood that the terms “comprise,” “comprises,”and/or “comprising,” “include,” “includes,” and/or “including,” whenused in this specification, specify the presence of stated features,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof.

It will be understood that the term “system,” “module,” and/or “block”used herein are one method to distinguish different components,elements, parts, section or assembly of different level in ascendingorder. However, the terms may be displaced by another expression if theyachieve the same purpose.

The term “module,” or “block,” as used herein, refers to logic embodiedin hardware or firmware, or to a collection of software instructions. Amodule or a block described herein may be implemented as software and/orhardware and may be stored in any type of non-transitorycomputer-readable medium or another storage device. In some embodiments,a software module/unit/block may be compiled and linked into anexecutable program. It will be appreciated that software modules can becallable from other modules/units/blocks or themselves, and/or may beinvoked in response to detected events or interrupts. Softwaremodules/units/blocks configured for execution on computing devices maybe provided on a computer-readable medium, such as a compact disc, adigital video disc, a flash drive, a magnetic disc, or any othertangible medium, or as a digital download (and can be originally storedin a compressed or installable format that needs installation,decompression, or decryption prior to execution). Such software code maybe stored, partially or fully, on a storage device of the executingcomputing device, for execution by the computing device. Softwareinstructions may be embedded in firmware, such as an ElectricallyProgrammable Read-Only-Memory (EPROM). It will be further appreciatedthat hardware modules/units/blocks may be included in connected logiccomponents, such as gates and flip-flops, and/or can be included inprogrammable units, such as programmable gate arrays or processors. Themodules/units/blocks or computing device functionality described hereinmay be implemented as software modules/units/blocks but may berepresented in hardware or firmware. In general, themodules/units/blocks described herein refer to logicalmodules/units/blocks that may be combined with othermodules/units/blocks or divided into sub-modules/sub-units/sub-blocksdespite their physical organization or storage. The description mayapply to a system, an engine, or a portion thereof.

It will be understood that when a module or block is referred to asbeing “connected to,” or “coupled to,” another module, or block, it maybe directly connected or coupled to, or communicate with the othermodule, or block, or an intervening unit, engine, module, or block maybe present, unless the context clearly indicates otherwise. As usedherein, the term “and/or” includes any and all combinations of one ormore of the associated listed items.

These and other features, and characteristics of the present disclosure,as well as the methods of operation and functions of the relatedelements of structure and the combination of parts and economies ofmanufacture, may become more apparent upon consideration of thefollowing description with reference to the accompanying drawings, allof which form a part of this disclosure. It is to be expresslyunderstood, however, that the drawings are for the purpose ofillustration and description only and are not intended to limit thescope of the present disclosure. It is understood that the drawings arenot to scale.

The present disclosure provides medical diagnosis and/or treatmentsystems having a collimator assembly with a short occupied radialdistance. The systems may include an adjustable aperture device (alsoreferred to herein as a collimator) positioned between the radiationsource and the bore of a scanner. The bore may include a detectingregion configured to accommodate a subject to be radiated such as apatient. The collimator may be configured to limit at least some portionof radiation rays emitted from the radiation source so that only thosetraveling parallel to a specified direction are allowed to pass throughand reach the subject and the detectors. The systems may also include afirst filter positioned between the radiation source and the collimator,and a second filter positioned between the collimator and the bore. Thefirst filter and the second filter may be configured to adjust thedistribution of the radiation impinging upon the subject.

The following descriptions are provided to help better understand thesystems and/or devices. This is not intended to limit the scope thepresent disclosure. For persons having ordinary skills in the art, acertain amount of variations, changes, and/or modifications may bededucted under the guidance of the present disclosure. Those variations,changes, and/or modifications do not depart from the scope of thepresent disclosure.

FIG. 1 is a schematic diagram illustrating an exemplary imaging system100 according to some embodiments of the present disclosure. As shown inFIG. 1, the imaging system 100 may include a scanner 110, a network 120,a terminal 130, a processing device 140, and a storage 150. In someembodiments, the scanner 110, the processing device 140, the storage150, and/or the terminal 130 may be connected to and/or communicate witheach other via a wireless connection (e.g., the network 120), a wiredconnection, or a combination thereof. The connections between thecomponents in the imaging system 100 may vary. For example, the scanner110 may be connected to the processing device 140 through the network120, as illustrated in FIG. 1. Alternatively, the scanner 110 may beconnected to the processing device 140 directly, via, for example, datacable. The storage 150 may be connected to the processing device 140through the network 120 or directly via data cable. The terminal 130 maybe connected to the processing device 140 through the network 120 ordirectly.

The scanner 110 may scan a subject and generate imaging data. Thesubject scanned may be biological or non-biological. For example, thesubject may include a patient, a man-made object (e.g., a phantom forcalibration), etc. As another example, the subject may include aspecific portion, organ, and/or tissue of a patient. For instance, thesubject may include the patient's head, brain, neck, body, shoulder,arm, thorax, cardiac, stomach, blood vessel, soft tissue, knee, feet, orthe like, or any combination thereof.

The scanner 110 may include a CT scanner, a PET scanner, a SPECTscanner, an X-ray or gamma ray scanner, a multi-modality scanner, or thelike, or any combination thereof. Exemplary multi-modality scanner mayinclude a CT-PET scanner.

The scanner 110 may send the data generated to the storage 150, theprocessing device 140, or the terminal 130 via the network 120. Forexample, the scanner 110 may be configured to scan the subject (e.g., apatient) to obtain imaging data based on a scanning of the subject. Insome embodiments, the scanner 110 may include a gantry, a radiationsource, a collimator assembly, a detector, a table, or the like, or anycombination thereof. The gantry may provide support for one or morecomponents of the scanner 110. The gantry may include a bore configuredto accommodate a subject (e.g., a patient) for scanning. To perform ascan (or during the radiation treatment), the radiation source 220 mayemit radiation beams (e.g., X-rays) toward a subject to be scanned. Thecollimator assembly may be configured to filter and/or regulate theradiation beams emitted from the radiation source. The radiation beamsmay impinge upon the subject and be detected by the detector forgenerating a medical image corresponding to the subject. The collimatorassembly may be located between the radiation source and the bore. Theheight (or the thickness) of the collimator assembly may have an impacton the radial distance between the radiation source and the bore.Generally, the shorter the height of the collimator assembly, thesmaller the radial distance the collimator assembly occupying and thesmaller the radial distance between the radiation source and the bore.The collimator assembly may include a first filter, an aperture deviceand the second filter. The shape of a surface of the first filter, whichfaces the aperture device, may conform to the shape of the aperturedevice. The shape of a surface of the second filter, which faces thebore of the scanner may conform to the shape of the bore. The collimatorassembly may occupy a shorter radial distance, which leads to a higherradiation efficiency.

The network 120 may include any suitable network that can facilitate theexchange of information and/or data for the imaging system 100. In someembodiments, one or more components of the imaging system 100 (e.g., thescanner 110, the terminal 130, the processing device 140, the storage150,) may communicate information and/or data with one or more othercomponents of the imaging system 100 via the network 120. For example,the processing device 140 may obtain the data for imaging from thescanner 110 via the network 120. As another example, the processingdevice 140 may obtain user instructions from the terminal 130 via thenetwork 120. The network 120 may be and/or include a public network(e.g., the Internet), a private network (e.g., a local area network(LAN), a wide area network (WAN)),), a wired network (e.g., an Ethernetnetwork), a wireless network (e.g., an 802.11 network, a Wi-Finetwork,), a cellular network (e.g., a Long-Term Evolution (LTE)network), a frame relay network, a virtual private network (“VPN”), asatellite network, a telephone network, routers, hubs, switches, servercomputers, and/or any combination thereof. Merely by way of example, thenetwork 120 may include a cable network, a wireline network, afiber-optic network, a telecommunications network, an intranet, awireless local area network (WLAN), a metropolitan area network (MAN), apublic telephone switched network (PSTN), a Bluetooth™ network, aZigBee™ network, a near-field communication (NFC) network, or the like,or any combination thereof. In some embodiments, the network 120 mayinclude one or more network access points. For example, the network 120may include wired and/or wireless network access points such as basestations and/or internet exchange points through which one or morecomponents of the Imaging system 100 may be connected to the network 120to exchange data and/or information. Merely by way of example, theprocessing device 140 may be configured to obtain a 3D image from thestorage 150 via the network 120.

The terminal 130 may include a mobile device 130-1, a tablet computer130-2, a laptop computer 130-3, or the like, or any combination thereof.In some embodiments, the mobile device 130-1 may include a smart homedevice, a wearable device, a mobile device, a virtual reality device, anaugmented reality device, or the like, or any combination thereof. Insome embodiments, the smart home device may include a smart lightingdevice, a control device of an intelligent electrical apparatus, a smartmonitoring device, a smart television, a smart video camera, aninterphone, or the like, or any combination thereof. In someembodiments, the wearable device may include a bracelet, footgear,eyeglasses, a helmet, a watch, clothing, a backpack, a smart accessory,or the like, or any combination thereof. In some embodiments, the mobiledevice may include a mobile phone, a personal digital assistant (PDA), alaptop, a tablet computer, or the like, or any combination thereof. Insome embodiments, the virtual reality device and/or the augmentedreality device may include a virtual reality helmet, virtual realityglasses, a virtual reality patch, an augmented reality helmet, augmentedreality glasses, an augmented reality patch, or the like, or anycombination thereof. For example, the virtual reality device and/or theaugmented reality device may include a Google Glass™, an Oculus Rift™, aHololens™, a Gear VR™, etc. In some embodiments, the terminal(s) 130 maybe part of the processing device 140. Merely by way of example, theterminal 130 may be configured to display a 3D image. The terminal 130may also be configured to transmit an instruction for scanning a subjectto the scanner 110. The terminal 130 may further be configured totransmit an instruction for measuring a radiation ray intensity and/orthe location of the radiation source

The processing device 140 may process data and/or information obtainedfrom the scanner 110, the terminal 130, and/or the storage 150. Forexample, the processing device 140 may obtain the data for imaging fromthe scanner 110 and/or the storage 150. In some embodiments, theprocessing device 140 may be a workstation or server. For example, theprocessing device 140 may be a single server or a server group. Theserver group may be centralized or distributed. In some embodiments, theprocessing device 140 may be local or remote. For example, theprocessing device 140 may access information and/or data stored in thescanner 110, the terminal 130, and/or the storage 150 via the network120. As another example, the processing device 140 may be directlyconnected to the scanner 110, the terminal 130 and/or the storage 150 toaccess stored information and/or data. In some embodiments, theprocessing device 140 may be implemented on a cloud platform. Merely byway of example, the cloud platform may include a private cloud, a publiccloud, a hybrid cloud, a community cloud, a distributed cloud, aninter-cloud, a multi-cloud, or the like, or any combination thereof.

The storage 150 may store data, instructions, and/or any otherinformation. In some embodiments, the storage 150 may store dataobtained from the terminal 130 and/or the processing device 140. In someembodiments, the storage 150 may store data and/or instructions that theprocessing device 140 and/or the terminal 130 may execute or use toperform exemplary methods described in the present disclosure. In someembodiments, the storage 150 may include a mass storage, removablestorage, a volatile read-and-write memory, a read-only memory (ROM), orthe like, or any combination thereof. Exemplary mass storage may includea magnetic disk, an optical disk, a solid-state drive, etc. Exemplaryremovable storage may include a flash drive, a floppy disk, an opticaldisk, a memory card, a zip disk, a magnetic tape, etc. Exemplaryvolatile read-and-write memory may include random-access memory (RAM).Exemplary RAM may include a dynamic RAM (DRAM), a double date ratesynchronous dynamic RAM (DDR SDRAM), a static RAM (SRAM), a thyristorRAM (T-RAM), and a zero-capacitor RAM (Z-RAM), etc. Exemplary ROM mayinclude a mask ROM (MROM), a programmable ROM (PROM), an erasableprogrammable ROM (EPROM), an electrically erasable programmable ROM(EEPROM), a compact disk ROM (CD-ROM), and a digital versatile disk ROM,etc. In some embodiments, the storage 150 may be implemented on a cloudplatform. Merely by way of example, the cloud platform may include aprivate cloud, a public cloud, a hybrid cloud, a community cloud, adistributed cloud, an inter-cloud, a multi-cloud, or the like, or anycombination thereof. The storage 150 may be configured to storeinformation and/or data associated with the scanner 110 and/or thesubject. For example, the storage 150 may be configured to storeinstructions for controlling a component (e.g., a collimator assembly)of the scanner 110. As another example, the storage 150 may beconfigured to store image data of the subject detected by the scanner110.

In some embodiments, the storage 150 may be connected to the network 120to communicate with one or more other components of the imaging system100 (e.g., the processing device 140, the terminal 130,). One or morecomponents of the imaging system 100 may access the data or instructionsstored in the storage 150 via the network 120. In some embodiments, thestorage 150 may be directly connected to or communicate with one or moreother components in the imaging system 100 (e.g., the scanner 110, theprocessing device 140, the terminal 130,). In some embodiments, thestorage 150 may be part of the processing device 140. Merely by way ofexample, the storage 150 may be configured to store a 3D image.

This description is intended to be illustrative, and not to limit thescope of the present disclosure. Many alternatives, modifications, andvariations will be apparent to those skilled in the art. The features,structures, methods, and other characteristics of the exemplaryembodiments described herein may be combined in various ways to obtainadditional and/or alternative exemplary embodiments. For example, thestorage 150 may be a data storage including cloud computing platforms,such as, public cloud, private cloud, community, and hybrid clouds, etc.However, those variations and modifications do not depart the scope ofthe present disclosure.

FIG. 2 is a schematic diagram illustrating an exemplary scanner 110according to some embodiments of the present disclosure. For brevity, aCT scanner is taken as an example of the scanner 110 for the purposes ofillustration. As illustrated in FIG. 2, the scanner 110 may include agantry (not shown), a radiation source 220, a collimator assembly 230, abore 240, a detector 250, a table (not shown), etc.

The gantry may support the radiation source 220 and the detector 250. Insome embodiments, the radiation source 220 and/or the detector 250 maybe configured on the gantry. In some embodiments, the radiation source220 and/or the detector 250 may move or rotate relative to the gantry.For example, the gantry may rotate around a rotation axis. The radiationsource 220 and/or the detector 250 may rotate with the rotation of thegantry. The rotation axis may coincide with the centerline axis of thebore.

The radiation source 220 may include an imaging source, a treatmentsource (e.g., X-ray source, etc.), or a combination thereof. To performa scan (or during the radiation treatment), the radiation source 220 mayemit radiation beams (e.g., X-rays) such as rays 260 and rays 280 towarda subject 270. The subject 270 may be placed on the table in the borepositioned at or near the center of the gantry. At least part of theradiation beams that the radiation source 220 emits (e.g., the rays280), after being attenuated by the subject 270, may impinge upon thedetector 250 and be measured by the detector 250.

The detector 250 may produce electrical signals indicative of theradiation beams received. The detector 250 may include one or moredetector modules having an arcuate structure including a plurality ofpixels and/or channels. The pixels may measure radiation beams andgenerate signals. The pixels may be arranged in a single row, two rows,or any other number of rows. The signals may be generated by respectivepixels in response to the radiation beams measured. The signals mayinclude different attributes (e.g., a radiation amplitude). For example,a signal may include a lower radiation amplitude when a radiation beamis measured traversing a higher density tissue (e.g., a bone tissue).The detector 250 may have any suitable shape. For example, the shape ofthe detector 250 may be flat, arc-shaped, circular, or the like, or acombination thereof. The fan angle of an arc-shaped detector array mayhave any suitable value. For example, the fan angle may be in the rangefrom 0° to 360°, from 30° to 270°, from 45° to 300°, etc. The fan anglemay be fixed or adjustable according to different conditions including,for example, a desired resolution of an image, the size of an image, thesensitivity of the detector, the stability of the detector, or the like,or a combination thereof.

The collimator assembly 230 may include a plurality of collimatorelements including, for example, at least one filter, an adjustableaperture device (also referred to herein as a collimator), a measurementdevice, or the like, or a combination thereof. The filter(s) may includea flat filter, a bowtie filter, a wedge filter, or the like, or anycombination thereof. The filter(s) may be configured to adjust at leastone portion of radiation rays and/or energy of radiation rays to reducethe energy of radiation rays, create a uniform radiation intensity, orthe like, or any combination thereof. For example, a flat filter may beconfigured to remove particular energies of X-rays that are damaging tothe subject and/or are not good for imaging. As another example, with abowtie filter, a lower dose of X-rays may be needed for imaging.

The adjustable aperture device may be configured to shape radiationbeams to a predetermined shape (or profile), for example, fan-shapedradiation beams. In some embodiments, the predetermined shape may bedifferent according to different anatomy (e.g., head, chest, etc.). Thepredetermined shape may be set by a user or according to the defaultsettings of the imaging system 100 (e.g., a scanning protocol, atreatment plan, etc.).

The measurement device may be configured to determine an intensity ofradiation beams and/or the location of the radiation source. In someembodiments, the measurement device may include an intensity sensor(e.g., a radiation power meter, or a radiation energy meter), a positionsensor (e.g., a position sensitive detector), or the like, or anycombination thereof. For example, the radiation power meter may includea probe, for example, a thermal probe and/or a photodiode probe, todetect the radiation beams it receives from the radiation source. Asanother example, the position sensitive detector may include aphotoconductive detector, a photovoltaic detector, a Schottky barrierdiodes detector, etc. In some embodiments, the measurement component mayinclude one or more detectors that may be similar or same as thedetector 250. For example, the measurement component may include onesingle detector configured to detect the intensity of radiation beams.As another example, the measurement component may include severaldetectors arranged in an array or matrix. The several detectors arrangedin an array or matrix may be configured to measure both intensity ofradiation beams and the location of radiation source.

The collimator assembly 230 may be located between the radiation source220 and the bore 240. The height (or the thickness) of the collimatorassembly 230 may have an impact on the radial distance between theradiation source 220 and the bore. Generally, the greater the height ofthe collimator assembly 230, the larger the radial distance thecollimator assembly 230 occupying and the larger the radial distancebetween the radiation source 220 and the bore 240. Conversely, a shorterheight of the collimator assembly 230 may result in a shorter radialdistance between the radiation source 220 and the bore 240, which leadsto a higher radiation efficiency. As used herein, a radial distancebetween the radiation source 220 and the bore 240 refers to a distancefrom the center of the radiation source 220 to the center of the bore240. The height of the collimator assembly 230 refers to the distancebetween the top surface of the collimator assembly 230 and the bottomsurface of the collimator assembly 230 along the center axis of thecollimator assembly 230 in a radial direction. The center axis of thecollimator assembly 230 traverses the center of the radiation source 220and the center of the bore 240. In some embodiments, the collimatorassembly 230 may include a first filter, an aperture device, and thesecond filter. The first filter and/or the second filter may include atleast one bowtie filter. The shape of a surface of the first filter,which faces the adjustable aperture device, may conform to the shape ofthe adjustable aperture device. The shape of a surface of the secondfilter, which faces the bore 240 of the scanner 110 may conform to theshape of the bore. And then the collimator assembly 230 may occupy ashorter radial distance which leads to a higher radiation efficiency.Detailed descriptions of the collimator assembly 230 may be foundelsewhere of the present disclosure (e.g., FIGS. 3-6 and thedescriptions thereof).

The descriptions above are intended to be illustrative, and not to limitthe scope of the present disclosure. Many alternatives, modifications,and variations will be apparent to those skilled in the art. Thefeatures, structures, methods, and other characteristics of theexemplary embodiments described herein may be combined in various waysto obtain additional and/or alternative exemplary embodiments. In someembodiments, the scanner 110 may further include an anti-scatter gridapparatus configured between the bore 240 and the detector 250. However,those variations and modifications do not depart the scope of thepresent disclosure.

FIG. 3 is a schematic diagram illustrating an exemplary collimatorassembly 300 according to some embodiments of the present disclosure.For brevity, a radiation source 320 and a bore 350 may be used fordescribing the collimator assembly 300. As illustrated in FIG. 3, thecollimator assembly 300 may include a first filter 342, an aperturedevice 346, and a second filter 348. In some embodiments, the firstfilter 342, the aperture device 346, and/or the second filter 348 may behoused in a carriage (not shown in FIG. 3) and detachable from thecarriage. In some embodiments, the first filter 342, the aperture device346, and/or the second filter 348 may move or rotate in the carriageaccording to a movement component. For example, the aperture device 346may rotate in the carriage according to a clinical condition associatedwith a subject to be scanned (e.g., a patient).

The first filter 342 may be configured to adjust the distribution ofradiation rays that impinge upon a subject. For example, the firstfilter 342 may lower the dose of X-rays that is needed for imaging. Asanother example, the first filter 342 may decrease dose X-rays to thesubject for treating. The first filter 342 may include a bowtie filterand/or a wedge filter. In some embodiments, the thickness of the firstfilter 342 may decrease along the direction from an edge to the centerof the first filter 342. For example, if most of the imaging mass (or aregion of interest) of the subject is located at the center of the bore350, the thickness of the subject may decrease from the center of thesubject to an edge of the subject. Therefore, the thickness of the firstfilter 342 at the center may be the minimal, and the thickness the firstfilter 342 at the edge may be greater than the thickness of the firstfilter 342 at the center. In some embodiments, the first filter 342 mayinclude a first surface facing the radiation source 320 and a secondsurface facing the aperture device 346. The shape of the first surfaceof the first filter 342 (i.e., the top surface of the first filter 342)may be in accordance with the size and/or shape of a subject or a regionof the subject to be scanned. The first surface may form a concave asshown in FIG. 3. In some embodiments, the concave may be configured toaccommodate other components of the collimator assembly 300, such as anX-ray intensity measurement device and/or an attenuating material. Theshape of the concave or the first surface may be determined based on aclinical condition such as the shape of the subject (or a regionthereof) to be scanned. For example, the length of the first surface ofthe first filter 342 (denoted as L shown in FIG. 3) corresponding to thehead of a human body may be less than that of the first filter 342corresponding to the chest of the body. In some embodiments, the lengthof the first surface of the first filter 342 may be adjusted accordingto the size and/or shape of the subject (or a region thereof). Forexample, the first surface of the first filter 342 may be extensible orelastic. Merely by way of example, if the head of the subject is to bescanned, the first filter 342 may be controlled by, for example, theprocessing device 140, to adjust the first surface to a shorter lengthin comparison with scanning the chest of the subject. As anotherexample, there may be a plurality of first filters 342 having differentcombinations of various sized first surfaces and second surfacesavailable. When a subject with a specific size and/or shape, a firstfilter 342 having a first surface with suitable size may be selected tobe placed in the collimator assembly 300.

The shape of the second surface of the first filter 342, which faces theaperture device 346, may conform to the shape of the aperture device346. For example, if the shape of the aperture device 346 includes anarc-shape (e.g., the arc-shape shown in FIG. 3), the shape of the secondsurface of the first filter 342 (i.e., the bottom surface of the firstfilter 342) may include an arc-shape according to the arc-shape of theaperture device 346. As another example, if the shape of the aperturedevice includes a flat shape (e.g., the flat shape of the aperturedevice 446 illustrated in FIG. 4), the shape of the second surface mayinclude a flat shape in accordance with the flat shape of the aperturedevice (i.e., the bottom surface of the first filter 442 shown in FIG.4). In some embodiments, the first filter 342 may include or be made ofa first material capable of absorbing radiation, which may include atleast one of plastic, graphite, metal (e.g., aluminum), or the like, ora combination thereof.

The aperture device 346 (also referred to herein as a collimator 346)may be configured to limit radiation beams emitted from the radiationsource 320. For example, the aperture device 346 may prevent at leastone portion of radiation beams emitted from the radiation source 320from being incident on the subject (e.g., human tissue). Alternativelyor additionally, the aperture device 346 may be configured to shape theradiation beams to a predetermined shape (or profile), for example,fan-shaped radiation rays. The predetermined shape may vary according tothe different anatomy of the subject (for example, head, chest, etc.).The radiation beams collimated by the aperture device 346 may beprojected to at least one portion of the subject. An area formed by theprojected radiation beams may comply with the shape of the at least oneportion of the subject to prevent other portions of the subject frombeing radiated. In some embodiments, the aperture device 346 may beconfigured to form an aperture in a specific shape. Radiation beamstraversing the aperture in the specific shape may be collimated to bethe predetermined shape corresponding to the specific shape of theaperture.

The second filter 348 may be configured to adjust the distribution ofradiation rays that impinge upon the subject. The second filter 348 maybe configured between the aperture device 346 and the bore 350. In someembodiments, the second filter 348 may be integrated into a coverencompassing the bore 350. The radiation rays adjusted by the secondfilter 348 may have a uniform intensity after being absorbed by thesubject. The second filter 348 may include a bowtie filter, and/or awedge filter, etc. In some embodiments, the thickness of the secondfilter 348 may decrease along a direction from an edge to a center ofthe second filter 348. For example, if most of the imaging mass (or aregion of interest) of the subject is located at the center of the bore350, the thickness of second filter 348 at the center may be the minimaland the thickness of second filter 348 at the edge may be greater thanthe thickness of the second filter 348 at the center. In someembodiments, the second filter 348 may include a third surface facingthe aperture device 346 and a fourth surface facing the bore 350. Theshape of the third surface of the second filter 348 (i.e., the topsurface of the second filter 348) may conform to the shape of theaperture device 346, such as an arc-shape (e.g., the arc-shape shown inFIG. 3). The shape of the fourth surface of the second filter 348 (i.e.,the bottom surface of the second filter 348) may conform to a shape ofthe bore 350. In some embodiments, the second filter 348 may include orbe made of a second material capable of absorbing radiation, which mayinclude at least one of plastic, graphite, metal (e.g., aluminum), orthe like, or any combination thereof. The second material may be thesame as or different from the first material. For example, the firstfilter 342 may include plastic, and the second filter 348 may includealuminum. As another example, the first filter 342 and the second filter348 may both include graphite.

In some embodiments, the height of the collimator assembly 300 (denotedH in FIG. 3) may range from 8 to 20 cm. In some embodiments, the rangeof the height of the collimator assembly 300 may be restricted in asub-range of 5.5 to 17.5 cm or 5 to 17 cm.

The collimator assembly 300 may be located between the radiation source320 and the bore 350. The first filter 342 may be located between theradiation source 320 and the aperture device 346, and the second filter348 may be located between the aperture device 346 and the bore 350.There may be a physical clearance between the second filter 348 and thebore 350 so that the collimator assembly 300 may move or rotate relativeto the bore 350. In some embodiments, the collimator assembly 300 maymove or rotate with the radiation source 320 by rotating the gantry ofthe imaging system 100.

In some embodiments, the collimator assembly 300 may include ameasurement component. The measurement component may be configured to,for example, determine at least one of the intensity of radiation beamsthat reaches the first filter 342 or the location of the radiationsource 320. In some embodiments, the measurement component may includean intensity sensor (e.g., an x-ray power meter, or an x-ray energymeter), a position sensor (e.g., a position sensitive detector), or thelike, or any combination thereof. For example, the x-ray power meter mayinclude a probe, for example, a thermal probe and/or a photodiode probe,to detect the radiation beams from the radiation source. As anotherexample, the position sensitive detector may include a photoconductivedetector, a photovoltaic detector, a Schottky barrier diodes detector,etc. In some embodiments, the measurement component may include one ormore detectors that may be similar or same as the detector 250. Forexample, the measurement component may include one single detectorconfigured to detect the intensity of radiation beams that reaches thefirst filter 342. As another example, the measurement component mayinclude several detectors arranged in an array or matrix. The severaldetectors arranged in an array or matrix may be configured to measureboth intensity of radiation beams that reaches the first filter 342 andthe location of the radiation source 320. The measurement component maybe located a suitable place in the collimator assembly 300. For example,the measurement component may be located in the space in the firstfilter 342, such as in the concave formed by the first surface of thefirst filter 342 (i.e., the top surface of the first filter 342).

In some embodiments, the collimator assembly 300 may include a motioncomponent (not shown). The motion component may be configured to moveone or more components of the collimator assembly 300, such as theaperture device 346, the first filter 342, and/or the second filter 348.The motion component may move the aperture device 346, the first filter342, and the second filter 348 separately or simultaneously. In someembodiments, the motion component may be integrated as an overall motiondevice with the rotation of one or more other components of the imagingsystem 100, for example, the gantry.

It should be noted that the collimator assembly 300 described above isprovided for illustration, not intended to limit the scope of thepresent disclosure. For persons having ordinary skill in the art,multiple variations and modifications may be reduced to practice in thelight of the present disclosure. However, those variations andmodifications do not depart from the scope of the present disclosure.For example, the collimator assembly 300 may further include a flatfilter (not shown in FIG. 3) in addition to the first and secondfilters. The flat filter may be configured to reduce particularradiation ray energies that are not ideal for imaging and harmful to thesubject (e.g., human tissue). As another example, the second filter 348may be omitted. In some embodiments, the first filter 342 may beconfigured in the collimator assembly 300 in a configuration that isdifferent from that shown in FIG. 3. For example, the first surface ofthe first filter 342 described above (e.g., the descriptions of theshape and/or size thereof) may face the aperture device 346, and thesecond surface of the first filter 342 may face the radiation source320. The first surface of the first filter 342 may bulge toward theradiation source 320. In some embodiments, instead of being part of thecollimator assembly 300, the second filter 348 may be integrated intothe bore 350.

FIG. 4 is a schematic diagram illustrating an exemplary collimatorassembly 400 according to some embodiments of the present disclosure.For brevity, a radiation source 420 and a bore 450 may be used fordescribing the collimator assembly 400. As illustrated in FIG. 4, thecollimator assembly 400 may include a first filter 442, an aperturedevice 446, and a second filter 448, which are respectively similar tothe first filter 342, the aperture device 346, and the second filter 348described above in connection with FIG. 3. For example, the first filter442 may include or be made of the material capable of absorbingradiation as the first filter 342. As another example, the first filter442 and/or the second filter 448 may include a bowtie filter as thefirst filter 342 and/or the second filter 348.

The first filter 442 may include a first surface, which faces theradiation source 420 (i.e., the top surface of the first filter 442),and a second surface, which faces the aperture device 446 (i.e., thebottom surface of the first filter 442). The shape of the second surfacemay conform to the shape of the aperture device 446. The second filter448 may include a third surface, which faces the aperture device 446(i.e., the top surface of the second filter 448), and a fourth surface,which faces the bore 450 (i.e., the bottom surface of the second filter448). The shape of the third surface of the second filter 448 mayconform to the shape of the aperture device 446. The shape of the fourthsurface of the second filter 448 may conform to the shape of the bore450.

The collimator assembly 400 illustrated in FIG. 4 and the collimatorassembly 300 illustrated in FIG. 3 may differ in the configurations oftheir components (e.g., the shapes and/or sizes of the first filter,aperture device, and/or second filter). For example, the shapes of thefirst filter 342 and the first filter 442 may be different; the shapesof the aperture device 346 and the aperture device 446 may be different;and/or the shapes of the second filter 348 and the second filter 448 maybe different. For example, the aperture device 346 of the collimatorassembly 300 may include a curve shape, and the second surface of thefirst filter 342 and the third surface of the second filter 348 may alsobe curved. On the other hand, the aperture device 446 of the collimatorassembly 400 may include a flat shape, and the second surface of thefirst filter 442 and the first surface of the second filter 448 may bothbe flat.

FIG. 5 is a schematic diagram illustrating an exemplary collimatorassembly 500 according to some embodiments of the present disclosure.For brevity, a radiation source 520 and a bore 550 may be used fordescribing the collimator assembly 500. As illustrated in FIG. 5, thecollimator assembly 500 may include a filter 541 (also referred toherein as a third filter 541), a first filter 542, an aperture device546, and a second filter 548, which are respectively similar to thefirst filter 342, aperture device 346, and second filter 348 describedabove in connection with FIG. 3. For example, the material of the firstfilter 542 may be the same as the first filter 342. As another example,the shape and/or size of the second filter 548 may be the same as theshape and/or size of the second filter 348.

The collimator assembly 500 illustrated in FIG. 5 and the collimatorassembly 300 illustrated in FIG. 3 differ in the configurations of theircomponents (e.g., the shapes and/or sizes of the first filter, aperturedevice, and/or second filter). For example, the collimator assembly 500may further including a third filter 541. The third filter 541 may belocated between the radiation source 520 and the first filter 542. Thethird filter 541 may be configured to reduce particular energies ofradiation rays that are not ideal for imaging or harmful to a subject(e.g., a human tissue). In some embodiments, the third filter 541 mayinclude any shape, such as a flat shape (as shown in FIG. 5). In someembodiments, the third filter 541 may include or be made of a materialthat can remove a part of the radiation rays and/or absorb another partof the radiation rays, which may include plastic, graphite, metal (e.g.,aluminum), or the like, or any combination thereof. The material of thethird filter 541 may be the same as or different from the materials ofthe first filter 542 and/or the second filter 548.

FIG. 6 is a schematic diagram illustrating an exemplary collimatorassembly 600 according to some embodiments of the present disclosure.For brevity, a radiation source 620 and a bore 650 may be used fordescribing the collimator assembly 600. As illustrated in FIG. 6, thecollimator assembly 600 may include a first filter 642, an aperturedevice 646, and a third filter 648, which are respectively similar tothe first filter 342, aperture device 346 described above in connectionwith FIG. 3. For example, the first filter 642 may include or be made ofthe material capable of absorbing radiation as the first filter 342. Asanother example, the first filter 642 may include a bowtie filter as thefirst filter 342.

The first filter 642 may include a first surface, which faces theradiation source 620 (i.e., the top surface of the first filter 642),and a second surface, which faces the aperture device 646 (i.e., thebottom surface of the first filter 642). The shape of the second surfacemay conform to the shape of the aperture device 646.

The collimator assembly 600 illustrated in FIG. 6 and the collimatorassembly 300 illustrated in FIG. 3 may differ in the configurations oftheir components (e.g., the shapes and/or sizes of the first filter,aperture device, and/or second filter). For example, the shape of theaperture device 646 of the collimator assembly 600 may conform to theshape of the bore 650, and the second surface of the first filter 642may form a convex as shown in FIG. 6. On the other hand, the secondsurface of the first 342 may form a concave as shown in FIG. 3. Asanother example, the collimator assembly 300 may include a second filter348 between the aperture device 346 and the bore 350. On the other hand,the collimator assembly 600 may include a filter between the aperturedevice 646 and the bore 650, and may include a third filter 648 betweenthe radiation source 620 and the first filter 642. The third filter 648may be configured to reduce particular energies of radiation rays thatare not ideal for imaging or harmful to a subject (e.g., human tissue)with any shape, such as a flat shape (as shown in FIG. 6). In someembodiments, the third filter 648 may include or be made of a materialthat can remove a part of the radiation rays and/or absorb another partof the radiation rays, which may include plastic, graphite, metal (e.g.,aluminum), or the like, or any combination thereof. The material of thethird filter 648 may be the same as or different from the material ofthe first filter 642. For instance, the first filter 642 may includeplastic and the third filter 648 may include aluminum, or the firstfilter 642 and the third filter 648 may both include graphite.

Having thus described the basic concepts, it may be rather apparent tothose skilled in the art after reading this detailed disclosure that theforegoing detailed disclosure is intended to be presented by way ofexample only and is not limiting. Various alterations, improvements, andmodifications may occur and are intended to those skilled in the art,though not expressly stated herein. These alterations, improvements, andmodifications are intended to be suggested by this disclosure and arewithin the spirit and scope of the exemplary embodiments of thisdisclosure.

Moreover, certain terminology has been used to describe embodiments ofthe present disclosure. For example, the terms “one embodiment,” “anembodiment,” and/or “some embodiments” mean that a particular feature,structure or characteristic described in connection with the embodimentis included in at least one embodiment of the present disclosure.Therefore, it is emphasized and should be appreciated that two or morereferences to “an embodiment” or “one embodiment” or “an alternativeembodiment” in various portions of this specification are notnecessarily all referring to the same embodiment. Furthermore, theparticular features, structures or characteristics may be combined assuitable in one or more embodiments of the present disclosure.

Further, it will be appreciated by one skilled in the art, aspects ofthe present disclosure may be illustrated and described herein in any ofa number of patentable classes or context including any new and usefulprocess, machine, manufacture, or composition of matter, or any new anduseful improvement thereof. Accordingly, aspects of the presentdisclosure may be implemented entirely hardware, entirely software(including firmware, resident software, micro-code,) or combiningsoftware and hardware implementation that may all generally be referredto herein as a “unit,” “module,” or “system.” Furthermore, aspects ofthe present disclosure may take the form of a computer program productembodied in one or more computer readable medium having computerreadable program code embodied thereon.

A computer-readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including electromagnetic, optical, or thelike, or any suitable combination thereof. A computer-readable signalmedium may be any computer-readable medium that is not acomputer-readable storage medium and that may communicate, propagate, ortransport a program for use by or in connection with an instructionexecution system, apparatus, or device. Program code embodied on acomputer readable signal medium may be transmitted using any appropriatemedium, including wireless, wireline, optical fiber cable, RF, or thelike, or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of thepresent disclosure may be written in any combination of one or moreprogramming languages, including a subject-oriented programming languagesuch as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB. NET,Python or the like, conventional procedural programming languages, suchas the “C” programming language, Visual Basic, Fortran 2003, Perl, COBOL2002, PHP, ABAP, dynamic programming languages such as Python, Ruby, andGroovy, or other programming languages. The program code may executeentirely on the user's computer, partly on the user's computer, as astand-alone software package, partly on the user's computer and partlyon a remote computer or entirely on the remote computer or server. Inthe latter scenario, the remote computer may be connected to the user'scomputer through any type of network, including a local area network(LAN) or a wide area network (WAN), or the connection may be made to anexternal computer (for example, through the Internet using an InternetService Provider) or in a cloud computing environment or offered as aservice such as a Software as a Service (SaaS).

Furthermore, the recited order of processing elements or sequences, orthe use of numbers, letters, or other designations, therefore, is notintended to limit the claimed processes and methods to any order exceptas may be specified in the claims. Although the above disclosurediscusses through various examples what is currently considered to be avariety of useful embodiments of the disclosure, it is to be understoodthat such detail is solely for that purpose and that the appended claimsare not limited to the disclosed embodiments, but, on the contrary, areintended to cover modifications and equivalent arrangements that arewithin the spirit and scope of the disclosed embodiments. For example,although the implementation of various components described above may beembodied in a hardware device, it may also be implemented as asoftware-only solution, e.g., an installation on an existing server ormobile device.

Similarly, it should be appreciated that in the foregoing description ofembodiments of the present disclosure, various features are sometimesgrouped together in a single embodiment, figure, or description thereoffor the purpose of streamlining the disclosure aiding in theunderstanding of one or more of the various embodiments. This method ofdisclosure, however, is not to be interpreted as reflecting an intentionthat the claimed subject matter requires more features than areexpressly recited in each claim. Rather, claimed subject matter may liein less than all features of a single foregoing disclosed embodiment.

What is claimed is:
 1. A device, comprising: a collimator positionedbetween a radiation source of a scanner and a bore of the scanner, thebore including a detecting region configured to accommodate a subject,the collimator being configured to prevent at least one portion ofradiation rays emitted from the radiation source from being incident onthe subject; a first filter positioned between the radiation source andthe collimator; and a second filter positioned between the collimatorand the bore, the first filter and the second filter being configured toadjust a distribution of radiation impinging upon the subject.
 2. Thedevice of claim 1, wherein the second filter includes a first surfacefacing the collimator, a shape of the first surface conforming to ashape of the collimator.
 3. The device of claim 2, wherein the secondfilter includes a second surface facing the bore, a shape of the secondsurface conforming to a shape of the bore.
 4. The device of claim 1,wherein the second filter is integrated into a cover encompassing thebore.
 5. The device of claim 1, wherein the first filter includes asurface facing the collimator, a shape of the surface facing thecollimator conforming to a shape of the collimator.
 6. The device ofclaim 1, wherein the first filter includes at least one of a bowtiefilter or a wedge filter.
 7. The device of claim 1, wherein the secondfilter includes at least one of a bowtie filter or a wedge filter. 8.The device of claim 1, wherein the first filter includes a firstmaterial, and the second filter includes a second material, the firstmaterial or the second material including at least one of plastic,graphite, or aluminum.
 9. The device of claim 8, wherein the firstmaterial is different from the second material.
 10. The device of claim8, wherein the first material is same as the second material.
 11. Thedevice of claim 1, further comprising a measurement component configuredto determine at least one of an intensity of radiation beams thatreaches the first filter or a location of the radiation source.
 12. Thedevice of claim 11, wherein the first filter has a surface facing theradiation source, the surface forming a concave, the measurementcomponent being located in the concave.
 13. The device of claim 1,further comprising a motion component configured to move at least one ofthe collimator, the first filter, or the second filter.
 14. The deviceof claim 1, further comprising a third filter, the third filter being aflat filter.
 15. A system, comprising: a scanner including a radiationsource and a bore, the bore including a detecting region configured toaccommodate a subject; and a collimator assembly positioned between theradiation source and the bore of the scanner, the collimator assemblyincluding: a collimator positioned between the radiation source and afirst filter, the collimator being configured to prevent at least oneportion of radiation emitted from the radiation source from beingincident on the subject; a first filter positioned between the radiationsource and the collimator; and a second filter positioned between thecollimator and the bore, the first filter and the second filter beingconfigured to adjust a distribution of radiation impinging upon thesubject.
 16. The system of claim 15, wherein the second filter includesa first surface facing the collimator, a shape of the first surfaceconforming to a shape of the collimator.
 17. The system of claim 16,wherein the second filter further includes a second surface facing thebore, a shape of the second surface conforming to a shape of the bore.18. The system of claim 15, wherein the first filter includes a surfacefacing the collimator, a shape of the surface corresponding to thecollimator conforming to a shape of the collimator.
 19. The system ofclaim 15, wherein the first filter includes at least one of a bowtiefilter or a wedge filter.
 20. The system of claim 15, wherein the secondfilter includes at least one of a bowtie filter or a wedge filter.